Battery degraded to 80%

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i-Tray
Posts: 24
Joined: Sun Jun 16, 2019 9:57 am
Location: United Kingdom

Re: Battery degraded to 80%

Post by i-Tray » Mon Apr 05, 2021 7:22 pm

symos wrote:
Wed Jan 27, 2021 3:35 pm
I'm looking to buy a used I-pace and are asking for a battery state of health report.

The first one I got said the health was at 81.5% (which is not normal for a car with only 4.500kms and a little over a year old).

However, the screenshot was from the main screen (not individual cells) and said "test in progress". So I asked for a re-test and individual cell report. The one I got then showed the individual cells alright, but not the state of health, instead it showed the voltage.
Hi symos. I'm no battery expert, but from my experience with a faulty battery the dealerships can't produce a capacity reading for the battery (otherwise they'd have done that on my first couple of visits) and the car & app will both say "100% charged" which as you know is different to the battery being 100% healthy; so I'd ask them to explain more about what that 81.5% actually represents. Surely it wasn't just 'state of charge'? On the plus side, the voltage readings from the cell checks seem to confirm they're working fine - it was the individual cell checks that got the dealership to accept my battery had problems - so if the dealership stands by the cell checks then I'd hope that's enough to be confident the battery's ok.

And do let us know if the dealership explains anything more about the 81.5% they first quoted you.
First Edition, Photon red, 22" wheels.

i-Tray
Posts: 24
Joined: Sun Jun 16, 2019 9:57 am
Location: United Kingdom

Re: Battery degraded to 80%

Post by i-Tray » Mon Apr 05, 2021 7:33 pm

symos wrote:
Wed Jan 27, 2021 3:35 pm
All cells were at 10.7 and one at 10.8. But don't know if that's immediately translatable to state of health or not.
Actually, Symos, looking back at my cell checks I'm not so sure the readings you got are a positive sign. My cells checks gave 12.3v on all cells except one at 11.9v (the faulty one). So 10.7v or 10.8v readings sound bad.... again, I'd challenge the dealership to explain, but they may only have 1 tech trained up on this stuff so don't settle for the salesman's patter.

Maybe someone here can tell us what the cells' voltage should be as standard?
First Edition, Photon red, 22" wheels.

Maxwell_400
Posts: 429
Joined: Mon Oct 14, 2019 10:09 am
Location: Norway

Re: Battery degraded to 80%

Post by Maxwell_400 » Tue Apr 06, 2021 7:37 am

i-Tray wrote:
Mon Apr 05, 2021 7:33 pm
symos wrote:
Wed Jan 27, 2021 3:35 pm
All cells were at 10.7 and one at 10.8. But don't know if that's immediately translatable to state of health or not.
Actually, Symos, looking back at my cell checks I'm not so sure the readings you got are a positive sign. My cells checks gave 12.3v on all cells except one at 11.9v (the faulty one). So 10.7v or 10.8v readings sound bad.... again, I'd challenge the dealership to explain, but they may only have 1 tech trained up on this stuff so don't settle for the salesman's patter.

Maybe someone here can tell us what the cells' voltage should be as standard?
Fully single charged cell is 4.15 volts but due to inadequate cell balancing they can be as low as 4.1 volts. A module (4 in parallel, 3 i series) should then be in the range 12.3 to 12.45.
I-Pace SE++, MY20, 18" summer & winter, no panoroof, towbar, spare wheel, 20C, TCU 19.2, BECS: BP-AAE-BC-AC-BE

Captain.Plummet
Posts: 502
Joined: Thu Mar 14, 2019 5:26 pm
Location: UK

Re: Battery degraded to 80%

Post by Captain.Plummet » Tue Apr 06, 2021 8:41 am

The first thing to do is to discharge to around 15% SoC and then charge to full on a 7kW wall charger or granny charger and leave the car connected for 48 hours. This will ensure that the cells are balanced. Reset the GoM and see what range you have.
My battery policy is to always to charge to 100% at home and work on 7kW chargers and to leave the car connected whenever possible. I avoid charging at rapid chargers but when I have to, which is rare, I only use 50kW devices, only charge to the level I need and never charge above 80%.
Consequently the car is plugged in at home or my destination more or less every night and stands at 100% charge most if the time.
In 35,000 miles the GoM on my car shows 261 miles at 100% and I haven’t reset it in months. Temperatures dropped below zero overnight too.
There are many threads about battery management but the most important advice is not to become obsessed with charging speed. Optimise low speed home and destination charging whenever possible and don’t worry about 100% SoC when using AC chargers.

symos
Posts: 41
Joined: Wed Dec 02, 2020 9:11 pm
Location: Swaziland

Re: Battery degraded to 80%

Post by symos » Tue Apr 06, 2021 10:00 am

i-Tray wrote:
Mon Apr 05, 2021 7:22 pm
Hi symos. I'm no battery expert, but from my experience with a faulty battery the dealerships can't produce a capacity reading for the battery (otherwise they'd have done that on my first couple of visits) and the car & app will both say "100% charged" which as you know is different to the battery being 100% healthy; so I'd ask them to explain more about what that 81.5% actually represents. Surely it wasn't just 'state of charge'? On the plus side, the voltage readings from the cell checks seem to confirm they're working fine - it was the individual cell checks that got the dealership to accept my battery had problems - so if the dealership stands by the cell checks then I'd hope that's enough to be confident the battery's ok.

And do let us know if the dealership explains anything more about the 81.5% they first quoted you.
Hello. I didn't end up buying that car, I've since bought another one with 97% battery health. I've been driving it for the last few weeks and I'm happy so far.

However, the number quoted was not state of charge, but a state of health report. Now, I can't vouch for how trustworthy this report is, but it's definitely something specific to the health of the battery, unrelated to SoC.

Regarding voltage, I'm no expert so don't have an opinion. Maxwell_400 says they should be in the range of 12.3 to 12.45, as each cell is 4.15V.
Sciencegeek (in the last post on this page):
viewtopic.php?t=1156&start=10
says each cell is 3.6V so the module is 10.8V, which is more consistent with the report I got.

Maxwell_400
Posts: 429
Joined: Mon Oct 14, 2019 10:09 am
Location: Norway

Re: Battery degraded to 80%

Post by Maxwell_400 » Tue Apr 06, 2021 10:12 am

symos wrote:
Tue Apr 06, 2021 10:00 am
i-Tray wrote:
Mon Apr 05, 2021 7:22 pm
Hi symos. I'm no battery expert, but from my experience with a faulty battery the dealerships can't produce a capacity reading for the battery (otherwise they'd have done that on my first couple of visits) and the car & app will both say "100% charged" which as you know is different to the battery being 100% healthy; so I'd ask them to explain more about what that 81.5% actually represents. Surely it wasn't just 'state of charge'? On the plus side, the voltage readings from the cell checks seem to confirm they're working fine - it was the individual cell checks that got the dealership to accept my battery had problems - so if the dealership stands by the cell checks then I'd hope that's enough to be confident the battery's ok.

And do let us know if the dealership explains anything more about the 81.5% they first quoted you.
Hello. I didn't end up buying that car, I've since bought another one with 97% battery health. I've been driving it for the last few weeks and I'm happy so far.

However, the number quoted was not state of charge, but a state of health report. Now, I can't vouch for how trustworthy this report is, but it's definitely something specific to the health of the battery, unrelated to SoC.

Regarding voltage, I'm no expert so don't have an opinion. Maxwell_400 says they should be in the range of 12.3 to 12.45, as each cell is 4.15V.
Sciencegeek (in the last post on this page):
viewtopic.php?t=1156&start=10
says each cell is 3.6V so the module is 10.8V, which is more consistent with the report I got.
Nominal voltage is 3.6, when fully charged they have 4.15 volts maximum.
I-Pace SE++, MY20, 18" summer & winter, no panoroof, towbar, spare wheel, 20C, TCU 19.2, BECS: BP-AAE-BC-AC-BE

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